html,
body,
#app {
    height: 100%;
    margin: 0;
    padding: 0;
}
nav{
    margin: 0;
    padding: 0;
}
.conter{
    display: flex;
    justify-content: center;
    align-items: center;
}
ul,
li {
  list-style: none; 
  margin: 0;
  padding: 0; 
}